Coaxial jack



Jan. 22, 1957 R. H. TANNER ET AL 2,779,005

coAxIAL JACK Filed Sept. 6, 1955 i3 3019 zo and tinto which the 'transmission :lines jen'ter. known, the characteristic iimpedanceo'f a high lieq'ehcy coaxial line is related to :the lcapacitance relation "with United States PatentQ Y,

between coaxial vtransmission lines. l.

A vmajor problem, encountered in the Yuse Aof coaxial "transmission '-lines, is 'that relating "to the rapid lchanging of the connections of a coaxial iline 'to Lother lassociated ines, having the same 1or different characteristics, so 'as n fto maintain 'constantt'he characteristic'fimpec'lance "between Avthe different lines. In one type of )prior *switch -tlesi'g'ited 'for v'this purpose, Awhich selectively connects 'or disconnedts only the Iinner conductors in changing "theconn'ection '-'from one li'ne Ato another, the mechanism includes "a chamber in which the switching elements are disposed AS is `well respect -to the concentric spacing 'bi'et'ween inner and outer conductors of the line. Due `to 'the `elfec'toff lthe chamber .within the jack, which iis snecessarily large in relation to thecrosssectionarea ofthetransmission lines, and the disposal of the inner conductors of the transniissionlines therewithin, vthere is :a i'tendency *to-setgup undesirel -reilections of energy fand vstanding vfaves`- in the connected line, resulting from a mismatch of the impedance between the transmission lines and the chamber within the jack, with a consequent loss of energy.

It is an object of this invention to provide a novel jack, normally adapted to connect a pair of associated coaxial lines, whereby this connection may be broken and any one of a plurality of associated coaxial transmission lines connected to a particular member of the pair, with the characteristic impedance associated therewith tending to be constant.

It is a further object of the present invention to provide a novel jack with the foregoing characteristics and to additionally include means for connecting any one of a plurality of coaxial associated transmission lines to either member of the pair with the characteristic impedance associated therewith tending to be constant.

It is another object of this invention to provide a novel coaxial jack with the foregoing characteristics and to include only a small amount of reections of energy and standing Waves on the connected line.

A further object of this invention is to provide a novel jack with the foregoing characteristics having an improved capacitance relationship with respect to the concentric spacing between the conductors of the transmission lines within the jack.

These and other objects of one embodiment of the invention are obtained by providing a coaxial jack comv prising a bored and chambered metallic housing, the bored sections extending to the chamber horizontally and vertically in a somewhat T-shaped manner, the switching elements beingv so arranged within the chamber that the continuity of the shielding of the engaged inner conductors is maintained and in which the switching elements and chamber are so formed that the tendency to set up undesired reections of energy and standing waves is reduced.

, 2,779,005 Raterited 18.11.22, 1.957

ICC

'Abetter understandingof vthe invention `will beobtained iby referring t'o 'the following description, taken vin conijunction withthe accompanying drawing, in which:

Pig'. 1 illustrates asgreatly enlarged diagrammatic View, lipaiftlyfini-section, of the jack of this invention mounted fon 'a jack panel; t and Fig. 2 illustrates across 'section of "the j-'ack taken at AA in the direction of the arrows.

:Coh'sieiing 'the Ldrawing, the housing fof 'the `jaek of :the invention-con'sists of foppositely fdi'spo'sed metallic sections '11 fand f2 extending in 'a horizontal :direction and fa vertical lmetallic fsection 3 'intersecting therewith t'o fform la somewhat `Tsh`aped structure with 'a chamber 4 {thereywithin, t'heise'cti'ons foiming the continuous outer confl'uct'or '.for the coaxial 4jacle Axially fdispose'd within fthe `bore-d 1 sect-ion lsare the 1innerconductors f5 :and f6, conducltorSbeing Pama'n'ged'in Vslidable andfelectria'l conducting relation partially within conductor v6, with fthe former, feonuctorffs, in 'yieldabie association with :the flatter by virtue or `spring 17, :one extremity fof conductor a6 lbeing ibifurcatel at 18 so 'that the 'inner conductor l'of la coaxial transmission line may tbe connected ther'eto and -fo'ne lexftrenityroffconductor 5 having =contact 9 secured thereto.

- V.iiitially 'disposedf'ihlthe section 3 iis the -fix'e'dfcodudtor 13 which has contact 14 secured thereto at #one `loffits .extremities and which iis bifurea'te'd at =its :other extremity 115,1to which the inner conductor xof the respective coaxial transmission Iline irnajy '-b'e connected.

.attention 1v Eby iin-sulatinfg dises A16 4anni 3117-, -dis'c 116 lbeing xed to conductor 6 and to the inside surface f-section 1 and disc 17 being fixed to conductor 5 and being in slidable engagement within the notch 18 which is arranged so that disc 17 cannot rotate. Conductor 10 is supported by insulating discs 19, 20 which are secured to the inside surface of section 2 and in which conductor 10 is slidingly tted. Conductor 13 is supported by insulating discs 21, 22, 23 which are secured to conductor 13 and to the inside surface of section 3.

Contact 14 is provided with a central aperture 24 through which insulating rod 25 reciprocates, one extremity of the rod 25 being secured to contact 9 and the other extremity being provided with threads 26 suitablefor adjustable engagement with threads 27 provided in contact 12 and in the associated extremity of conductor 10. Contacts 9 and 12 and the inside of chamber 4 have a configuration such that when either one of these movable contacts becomes engaged with xed contact 14, the characteristic impedance presented by the chamber 4 should approach the characteristic impedance of the conductors 5, 6 and 13 or 10 and 13. ln the presented embodiment, outer surfaces of contacts 9 and 12 and the inner surface of chamber 14 are mutually tapered and coaxial so that the concentric spacing between the inner conductors 5, 6 and 13 or 10 and 13and the inside surface of sections 1 and 2 is continued into chamber 4 of the jack. It is preferable that the insulating discs 16, 17, 19, 20, 21, 22, 23 and the rod 25 be constructed of polystyrene due to the lowdielectric loss characteristic of that material.

Any desired number of jacks of this invention may be mounted on panel 28 and secured thereto by fasteners such as screws 29, 30 as shown in the drawing.

In the operation of the jack, assuming as shown that conductor 5 is connected to conductor 13 through contacts 9 and 14, contact 12 will close the opening in section 2 of the housing of the jack thus maintaining the continuity of the inner surface of chamber 4 and thereby preventing the tendency to set up undesired reections of energy and the creation of standing waves which would occur if the section 2 were lett open. The above tendency is prevented also by the configuration of contact 9 and the inside of chamber 4 which, in the example shown in the drawing, is tapered, thus reducing the eilect of a change in the concentric spacing of the inner and outer conductors. Since Contact 9 or 12 is spaced apart from contact 14 when disengaged therefrom, the capacitance between contacts 9 and 14 or 12 and 14 is kept at a minimum.

When it is desired to disconnect conductor 5 from conductor 13 and to connect conductors 16 and 13, the inner conductor of the coaxial line associated with the inner conductor is inserted in the bored section 2 to engage with, and `to move, conductor 10 so that contact 12 engages with Contact 14. The later removal of the inner conductor of theccaxial line associated with inner conductor 10, when it is desired to reconnect conductor 5 to conductor 13, permits spring 7 to cause contact 12 to become disengaged from contact 14.

When it is desired to connect conductor 5 to conductor 10, the incoming coaxial line at section 3 is disconnected and a selected coaxial line is inserted in section 2 of the jack, without any forward linear movement of the inner conductor 10, and rotated so that contact 12 of conductor 10 engages with contact 14, by virtue of threads 26, 27, contact 9 being held in engagement with contact 14.y

Since any desired number of jacks may be mounted on the jack panel 28, interconnection of the coaxial transmission lines may be obtained by means of coaxial patching cords.

The jack of this invention, therefore, when employed with coaxial transmission lines, reduces the tendency to mismatch the impedanccs and in addition provides opcrational flexibility and an instant availability of spare equipment with a consequent reduction in cost in the operation of the lines, Y

What is claimed is: 1. A jack for coaxial transmission lines comprising:

i a hollow metallic housing having a chamber therewithin to the fixed conductive member being apertured and dis-i posed between the movable conductive members; an insulated rod member disposed to reciprocate through th said aperture and having one extremity secured to a selected Contact member of one of the movable conductive members and the other extremity arranged so that the other movable conductive member and its associated con tact member may be rotatably advanced or retracted on the rod member; means associated with the selected contact member to prevent the rotation of the rod member, the movable contact members being arranged so that when one of these members is in engagement with the apertured contact member the other movable contact member, being in the retracted position, is in engagement with the housing so as to provide a substantial continuation of the inner surface of the chamber and means for urging the selected contact member into yieldable engagement with the apertured member.

2. A jack in accordance with claim 1 in which said chamber and said contact members secured to the mov- References Cited in the le of this patent UNITED STATES PATENTS Chaffee Mar. 18, 1941 2,475,464 Shankweiler July 5, 1949 

